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Add radiant to a geo setup?

We're building a new 5000 sqft house. It'll have 3 zones, using three 400ft vertical wells. We're in Maryland, just outside of DC. It's going to be foam insulated. I don't know that it qualifies as "super insulated" but it's more than would typically be done with batts. The old brick-on-block literally had NO insulation in the walls, just an air gap from 1" furring strips!

I don't have all the specifics of the setup. It's a Water Furnace system. I believe it does not currently include a desuperheater.

My question is whether it's worthwhile to add a radiant floor setup in addition to the forced air ducting. All of the flooring likely to have floor radiant would be wood floor. The whole house will be foam insulated and conditioned. So there won't be any places with a crawl space under them.

I'm wondering if it'd be worthwhile adding some radiant loops under certain parts of the house. Like the walkable areas under the kitchen, 1st floor hallways and an office. My thought here is to just take the chill off the floor, not heat the whole space. We get a pretty dramatic range of temperature changes around here, especially at the change of seasons. So there are times where it's nice to have the floor warmed up a little without heating the whole area.

We've had electric underfloor in bathrooms and are budgeted to have that again in the master and children's bath. Those are on the 2nd floor so I'm not sure how viable it would be to integrate them along with the 1st floor. But the time to warm them up would likely be pretty close to each other. Each floor has it's own zone.

Budget today might not allow for adding a whole radiant setup. But before I go having drywall put up underneath these areas I'm debating whether it'd be worth putting up some underfloor tubing and panels. And as budgets allow later tying them back into the geo setup.

Yeah, it doesn't always seem like it costs much to "do it all" now, but the numbers pile up. At some point adding a few thousand here and there starts cutting into the budget for other materials. But I'm willing to consider some infrastructure things now, instead of paying money to rip things apart later. As in, better to put in some tubing now vs paying to demo, replace and repaint the whole drywall ceiling to do it later.

The good part is I've got blank slate to work with here. Nothing's in yet and my hope is if something like this is worthwhile to make sure the mechanical room is sized and laid out to allow for additions like this or changes later.

It's a Water Furnace system. I believe it does not currently include a desuperheater.

My question is whether it's worthwhile to add a radiant floor setup in addition to the forced air ducting. All of the flooring likely to have floor radiant would be wood floor. The whole house will be foam insulated and conditioned. So there won't be any places with a crawl space under them.

I'm wondering if it'd be worthwhile adding some radiant loops under certain parts of the house. Like the walkable areas under the kitchen, 1st floor hallways and an office. My thought here is to just take the chill off the floor, not heat the whole space. We get a pretty dramatic range of temperature changes around here, especially at the change of seasons. So there are times where it's nice to have the floor warmed up a little without heating the whole area.

If a GEO is involved for Radiant heating, then I would highly recommend that the water temp be no higher than 100F at full heat. Other than this, radiant floor is okay anywhere.

Warning! geo forced air units, and geo radiant units are two entirely different machines. Also adding load to a heat exchanger later is also not adviseable unless planned for upfront. Geo is a great water to water option but the machine would need to be a water to water, not a water to air.
Hope this helps.
Eric

Eric got it right, you can't just add radiant to the geothermal, this needs to be designed for. You might be able to drill one more well and install a WaterFurnace NSW025 or NSW018 to heat the water for a small radiant floor system. Or you could upgrade your waterfurnace water to air unit for a Synergy 3D that heats both air and water and cools air. Radiant flooring is no small add on, it can literally double the cost of your system and not all geo companies do radiant so whoever you selected might not be able to.

You really need to talk to your contractor because there are a lot of issues here and it may be to late to add properly. Just don't go electric mats or electric heated water for radiant it will offset all the savings of the geo.

Eric got it right, you can't just add radiant to the geothermal, this needs to be designed for. You might be able to drill one more well and install a WaterFurnace NSW025 or NSW018 to heat the water for a small radiant floor system. Or you could upgrade your waterfurnace water to air unit for a Synergy 3D that heats both air and water and cools air. Radiant flooring is no small add on, it can literally double the cost of your system and not all geo companies do radiant so whoever you selected might not be able to.

You really need to talk to your contractor because there are a lot of issues here and it may be to late to add properly. Just don't go electric mats or electric heated water for radiant it will offset all the savings of the geo.

Good points. I'll be discussing this in more detail with the subcontractor this week.

The only place electric mats would be going is in two bathrooms and then be on a pretty narrow schedule. As in only during wake-up times. The rest of the time they'd be off. Their only purpose being to warm the tile flooring just a bit. We've neighbors that had them set up with just a thermostat (without any timers) and they complained of the cost. Well, yeah, no surprise there.